/* SPDX-License-Identifier: Apache-2.0
*
* The OpenSearch Contributors require contributions made to
* this file be licensed under the Apache-2.0 license or a
* compatible open source license.
*/
/*
* Modifications Copyright OpenSearch Contributors. See
* GitHub history for details.
*
*  Licensed to Elasticsearch B.V. under one or more contributor
*  license agreements. See the NOTICE file distributed with
*  this work for additional information regarding copyright
*  ownership. Elasticsearch B.V. licenses this file to you under
*  the Apache License, Version 2.0 (the "License"); you may
*  not use this file except in compliance with the License.
*  You may obtain a copy of the License at
*
* 	http://www.apache.org/licenses/LICENSE-2.0
*
*  Unless required by applicable law or agreed to in writing,
*  software distributed under the License is distributed on an
*  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
*  KIND, either express or implied.  See the License for the
*  specific language governing permissions and limitations
*  under the License.
*/

using System.Collections.Generic;
using System.Runtime.Serialization;
using OpenSearch.Net.Utf8Json;

namespace OpenSearch.Client
{
	/// <summary>
	/// A tokenizer that breaks text into terms whenever it encounters a character which is in a defined set. It is mostly useful
	/// for cases where a simple custom tokenization is desired, and the overhead of use of <see cref="PatternTokenizer" /> is not acceptable.
	/// </summary>
	public interface ICharGroupTokenizer : ITokenizer
	{
		/// <summary>
		/// A list containing a list of characters to tokenize the string on. Whenever a character from this list is encountered, a
		/// new token is started. This accepts either single characters like eg. -, or character groups: whitespace, letter, digit,
		/// punctuation, symbol.
		/// </summary>
		[DataMember(Name ="tokenize_on_chars")]
		IEnumerable<string> TokenizeOnCharacters { get; set; }

		/// <summary>
		/// The maximum token length. If a token is seen that exceeds this length then
		/// it is split at <see cref="MaxTokenLength"/> intervals. Defaults to `255`.
		/// </summary>
		[DataMember(Name = "max_token_length")]
		[JsonFormatter(typeof(NullableStringIntFormatter))]
		int? MaxTokenLength { get; set; }
	}

	/// <inheritdoc cref="ICharGroupTokenizer" />
	public class CharGroupTokenizer : TokenizerBase, ICharGroupTokenizer
	{
		internal const string TokenizerType = "char_group";

		public CharGroupTokenizer() => Type = TokenizerType;

		/// <inheritdoc cref="ICharGroupTokenizer.TokenizeOnCharacters" />
		public IEnumerable<string> TokenizeOnCharacters { get; set; }

		/// <inheritdoc cref="ICharGroupTokenizer.MaxTokenLength" />
		public int? MaxTokenLength { get; set; }
	}

	/// <inheritdoc cref="ICharGroupTokenizer" />
	public class CharGroupTokenizerDescriptor
		: TokenizerDescriptorBase<CharGroupTokenizerDescriptor, ICharGroupTokenizer>, ICharGroupTokenizer
	{
		protected override string Type => CharGroupTokenizer.TokenizerType;

		IEnumerable<string> ICharGroupTokenizer.TokenizeOnCharacters { get; set; }
		int? ICharGroupTokenizer.MaxTokenLength { get; set; }

		/// <inheritdoc cref="ICharGroupTokenizer.TokenizeOnCharacters" />
		public CharGroupTokenizerDescriptor TokenizeOnCharacters(params string[] characters) =>
			Assign(characters, (a, v) => a.TokenizeOnCharacters = v);

		/// <inheritdoc cref="ICharGroupTokenizer.TokenizeOnCharacters" />
		public CharGroupTokenizerDescriptor TokenizeOnCharacters(IEnumerable<string> characters) =>
			Assign(characters, (a, v) => a.TokenizeOnCharacters = v);

		/// <inheritdoc cref="ICharGroupTokenizer.MaxTokenLength" />
		public CharGroupTokenizerDescriptor MaxTokenLength(int? maxTokenLength) =>
			Assign(maxTokenLength, (a, v) => a.MaxTokenLength = v);
	}
}